1. Field of the Invention
The present invention relates to a virtualized wireless communication system and an establishing method thereof.
2. Description of Related Art
With the advancement of wireless communication technologies, the development of various wireless communication protocols and wireless communication technologies has attracted more and more attention. As for a new wireless communication technology, it is necessary to evaluate its operation performance prior to practical application.
Generally speaking, there are two existing methods for evaluating a wireless communication technology. One is to set up a real communication system (e.g. including a plurality of nodes, servers, or the like) in a real-world environment, implement the developed wireless communication technology on the system and then evaluate its performance. However, obviously, such method is limited by site, maintenance, hardware cost, and the like. Thus, only in a small range of cases (with fewer communication nodes and smaller test area) can such evaluation be performed, which limits the accuracy and practicability of the evaluation.
The other method is the proposed method for evaluating a new technology's performance using a virtualized wireless network. For example, it has been proposed using a computer or a virtual machine to emulate nodes in a wireless network, so as to emulate behavior in the whole wireless communication network such as signal transmission, thereby evaluating the performance of a new technology. This method has some advantages such as low cost, good scalability, convenience and flexibility, and thus has a broader application prospect.
When using a virtualized wireless network, it is necessary to ensure conformity of the communication behavior of each virtual node with the behavior of nodes in a real wireless communication. For example, in a real wireless network, interference can exist between several mutually adjacent communication nodes. As a result, when these nodes attempt to transmit data at the same time, loss of data packets can occur because of the existence of interference. Therefore, when implementing a virtualized network, it is also necessary to emulate such interference case.
In addition, as for IEEE.802.11 protocol based communication, sending data and receiving data requires calculating the communication quality of signals. For example, when the signal-to-noise ratio of the received data packet is lower than a predetermined threshold, it is deemed that information carried by this data packet has changed to a great extent, and thus, this data packet can be discarded. Based on the teachings of the present invention, one of ordinary skill in the art can apply the essence and spirit contained herein to other communication protocols.
In the prior art, for example, in “Wireless Network Emulation System (WiNE), Final Technical Report” by Gavin Holland from HRL Laboratories, LLC on Mar. 30, 2005, a technical solution of emulating a wireless communication network using virtual machine and virtual node has been proposed. According to the prior art, virtual nodes are disposed on virtual machine, and virtual machines are provided on physical machine as many as possible, so as to emulate wireless nodes as many as possible. In this way, a wired network environment is actually used for emulating behavior of wireless communication. In the prior art, a virtual central server is provided in order to emulate communication behavior of wireless nodes, wherein, communication behavior (e.g. sending and receiving) of all the virtual nodes are firstly reported to this central server.
More specifically, this central server knows the arrangement of all the virtual nodes, the interferences there between, all the parameters of the emulated communication, and the like, and hereby decides communication behavior of each virtual node. As shown in FIG. 2, for example, when one virtual node 201 wishes to send out one data packet, it first reports this behavior to the central server 200. At this point, the central server determines other virtual nodes, e.g., 202 and 203, that can affect the sending behavior of virtual node 201, and decides whether or not virtual node 201 can successfully send out the data packet according to the statuses of these nodes. For example, when the central server 200 notes that another virtual node 202 is in the neighborhood of the virtual node 201 is also sending data (which indicates that wireless communication interference exists), the central server 200 calculates channel quality, interference intensity between the two virtual nodes, and the like based on preset parameters of the virtualized network, wherein, if the calculation result shows that the interference from the virtual node 202 is sufficiently strong to lead the virtual node 201 to fail to send signals, the central server 200 indicates that the virtual node 201 at this time failed to send signals. On the other hand, when the virtual node 201 receives data, the central server 200 calculates the signal-to-noise ratio of the received data packet based on behavior of other nodes, network environment, and communication parameters, wherein, if the signal-to-noise ratio is lower than a predetermined threshold, the virtual node 201 that is receiving data packet is instructed to discard the data packet and re-transmission is requested. When the server deems that the communication is successful, data packets among the respective virtual nodes are allowed to be transmitted via a wired network (not shown).
As can be seen from the above technical solution, the central server knows the communication conditions of all the virtual nodes and decides the behavior of the respective virtual nodes, thereby emulating wireless communication.
However, the above solution in the prior art has the following defects. Firstly, it can be seen that, all the communications are analyzed and assigned by the server. Thus, the central server becomes a performance bottleneck of the whole virtualized system. As the number of virtual nodes increases, the amount of the involved calculation can increase in a geometry level. Secondly, in this solution, each data packet must be initially analyzed and judged by the server, which impacts the real-time behavior of communication flows. Finally, purchasing a high-performance server will require a considerably high cost and expenditure, and the stability of the server also will become a critical factor for the whole virtualized network operation.